One could argue those children are the very people childless single people are expecting to be paying their social security payments on retirement, as well as the people who serve as the cashiers and waiters and waitresses when they're retired and going out to eat.

Raising your children to provide services to ungrateful childless single people, spending tens of thousands of dollars worth of time, and money, and only get back a fraction of it, seems more like doing a duty than self-gratification to me.

It's strange to see childless single people claim raising children as a selfish act, and they're being martyrs performing a selfless act relying on everyone else to serve them when they're old.